Inorganic metal oxide/organic polymer nanocomposites and method thereof

ABSTRACT

A synthetic method for preparation of hybrid inorganic/organic energetic nanocomposites is disclosed herein. The method employs the use of stable metal inorganic salts and organic solvents as well as an organic polymer with good solubility in the solvent system to produce novel nanocomposite energetic materials. In addition, fuel metal powders (particularly those that are oxophillic) can be incorporated into composition. This material has been characterized by thermal methods, energy-filtered transmission electron microscopy (EFTEM), N 2  adsoprtion/desorption methods, and Fourier-Transform (FT-IR) spectroscopy. According to these characterization methods the organic polymer phase fills the nanopores of the composite material, providing superb mixing of the component phases in the energetic nanocomposite.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a divisional of application Ser. No.10/186,468 filed on Jun. 28, 2002 entitled “Inorganic MetalOxide/Organic Polymer Nanocomposites an Method Thereof”

[0002] The United States Government has rights in this inventionpursuant to Contract No. W-7405-ENG-48 between the United StatesDepartment of Energy and the University of California for the operationof Lawrence Livermore National Laboratory.

BACKGROUND OF THE INVENTION

[0003] A composite is a mixture of at least two different componentmaterials. Composites typically display properties that are notattainable in any of their individual components. A nanocomposite is amixture of at least two different component materials where at least oneof the components has one or more dimensions (length, width, or height)in the nanometer region. Nanocomposites very often display new,interesting, and useful properties that the conventional compositematerials lack. The special properties displayed by nanocomposites aredue to their small building blocks. The very small particles of thecomponent materials have immense surface areas which result in therebeing a great deal of surface interfaces between them. This, in turn,influences the properties of the nanocomposites to a great extent. Inconventional composites the materials have sizes on the micrometer scalewith much less surface area and many fewer surface contacts andtherefore, less influence on the overall properties of the materials.

SUMMARY OF THE INVENTION

[0004] Aspects of the invention include a method comprising: dissolvinga metal ion salt in a solvent system to form a metal ion salt solution,wherein said solvent system is common to said metal ion salt and a givenpolymer; adding an epoxide to said metal ion salt solution to form anepoxide-containing metal ion salt solution; dissolving said polymer insaid solvent system to form a polymer solution; adding a portion of thepolymer solution to the epoxide-containing metal ion salt solution toform a polymer-containing, epoxide-containing metal ion salt solution;and stirring said a polymer-containing, epoxide-containing metal ionsalt solution until said solution gels.

[0005] A further aspect of the invention includes a nanocompositeproduced by the process comprising: dissolving a metal oxide salt in asolvent system to form a metal oxide salt solution, wherein said solventsystem is common to said metal oxide salt and a polymer; adding anepoxide to said metal oxide salt solution to form an epoxide-containingmetal oxide salt solution; dissolving said polymer in said solventsystem to form a polymer solution; adding a portion of the polymersolution to the polymer-containing metal oxide salt solution to form apolymer-containing, epoxide-containing metal oxide salt solution; andstirring said polymer-containing, epoxide-containing metal oxide saltsolution until said solution gels.

[0006] Another aspect of the invention includes a nanocompositecomprising: an inorganic sol-gel polymer phase comprising at least onemetal-oxide and at least one epoxide; and an interpenetrating organicpolymer phase entwined in said inorganic sol-gel phase.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a schematic representation of the microstructure of asol-gel derived Fe₂O₃/Viton A hybrid material.

[0008]FIG. 2 is the Fourier Transform infra-red (FT-IR) spectra of VitonA and a sol-gel Fe₂O₃/Viton A xerogel nanocomposite.

[0009]FIG. 3a is a Transmission electron micrograph of sol-gelFe₂O₃/Viton xerogel on a carbon grid. The particle is ˜600 nm indiameter.

[0010]FIG. 3b is an Energy filtered transmission electron micrograph(EFTEM) map for Fe in the sample.,

[0011]FIG. 3c is an EFTEM map for fluorine.

[0012]FIG. 4 is a photo of a freestanding cast Fe₂O₃/UFG Al aerogelnanocomposite monolith next to a US penny.

[0013]FIG. 5 is a photo of pressed part of sol-gel Fe₂O₃/UFG Al/Viton Ananocomposite with a density of 1.93 g/cc (˜75% TMD).

[0014]FIG. 6 shows the differential thermal analysis trace of sol-gelFe₂O₃/UFG Al/Viton nanocomposite performed in room air atmosphere with aheating rate of 20° C./minute.

DETAILED DESCRIPTION OF THE INVENTION

[0015] David et al in Chem. Mater., 7, 1957-1967,1995, and in U.S. Pat.No. 5,252,654 have prepared inorganic/organic composite materials andcharacterized them extensively. Their results indicate that thestructures contain interpenetrated or semi-interpenetrated organic andinorganic molecular networks intimately mixed.

[0016] Researchers have prepared nanocomposites for use as structuralmaterials, coatings, catalysts, electronics, and biomedicalapplications. Consumers are just starting to see the effects ofnanoscience in their everyday lives as commercial products inautomobiles, homes, and personal care products utilizing nanocompositeswhich have recently been developed. However, one field with much lessresearch in the areas of its nanoscience and nanocomposites, than theaforementioned fields, is that of energetic materials.

[0017] There are many different synthetic routes or methods to theproduction of nanocomposites. Some are made simply by powder blending ofmaterials (one or more of which is on the nanoscale). Others areprepared by chemically linking nanosized materials together. Stillothers are prepared by simply trapping or depositing one material intothe cavities, crevices, or pores of, another material. Sometimes thesemethods require expensive processing equipment or a great deal ofreaction time to ensure the homogeneous diffusion or blending of thematerials.

[0018] The present invention involves a new synthetic route to thepreparation of inorganic metal oxide/organic polymer nanocompositesinvolving the insitu deposition of both the inorganic and organic phasesfrom the same starting solution. The method can be applied to numerousmetal oxide materials in many different solvents and hundreds ofdifferent polymers to make thousands of different nanocomposites. Themethod takes advantage of simplicity of the epoxide addition syntheticmethod for the preparation of nanostructured inorganic metal oxides,which involves a sol-gel technique, such as described and claimed incopending U.S. application Ser. No. 09/581,234, filed Jun. 2, 2000 andSer. No. 09/586,426, filed Jun. 2, 2000, each assigned to the sameassignee.

[0019] Hybrid organic/inorganic nanocomposites comprise a sol-gelderived, metal oxide phase and molecularly entwined with an organicpolymer phase. Nanometer-sized ultra fine grain (UFG) aluminum orcommercially available micron-sized Al powder can be thoroughly mixedwith the metal oxide phase if desired. The resulting materials can beprocessed into a variety of forms. Fine powders, pressed pellets, freestanding cast monoliths, and thin films can be prepared using sol-gelmethodology. One example of an inorganic metal oxide/organic polymernanocomposite synthesis is the synthesis of an Fe₂O₃/Viton®A, A-100nanocomposite. Another example is an Fe₂O₃/Viton®A, A-100/Aluminumnanocomposite.

[0020] Viton®A, A-100 is an elastomer produced by Dupont Dow Elastomers,L. L. C. It is made of a partially fluorinated hydrocarbon polymer thatcontains water and is widely used in energetic materials as a binder.Viton®A, A-100 is effective as a dopant because it is soluble in amixture of about 70/30 ethanol/acetone by weight (herein after referredto as the 70/30 solvent mixture), a solvent mixture that is alsoamenable to the synthesis of Fe₂O₃ gels. The Fe₂O₃ gels are in turn usedto produce Fe₂O₃/Viton®A, A-100 nanocomposites and Fe₂O₃/Viton®A,A-100/Aluminum nanocomposites.

[0021] Fe₂O₃/Viton®A, A-100 nanocomposite materials can be formed bydissolving a known quantity of Viton®A, A-100 in the 70/30 solventmixture to make a clear, colorless Viton®A, A-100 solution. A hydratediron (III) salt, such as iron trichloride hexahydrate, is dissolved in aseparate portion of the 70/30 solvent mixture in order to form anFe³⁺-containing solution; Water is necessary for effective gelpreparation. The water can either come from the hydrated salt itself or,if an anhydrous salt is used, water may be added to the 70/30 solventmixture. A mixed solvent system, where one of the solvents is a lowmolecular weight ketone, e.g., acetone, or low molecular weight ester isvery important to successful nanocomposite synthesis. Viton®A, A-100 issoluble in very few solvents, i.e., low molecular weight ketones oresters, the only practical one for large-scale syntheses being acetone.The epoxide addition sol-gel method for iron-oxide gel materials is notpossible in a pure acetone system but is realized in many other commoninexpensive and non-toxic solvents. Mixed solvent systems, as long asone of the solvents is a low molecular weight ketone (e.g., acetone) orester (e.g., ethyl acetate) are capable of dissolving Viton®A, A-100.

[0022] Gel formation is induced by adding a proton scavenger (i.e., aspecies capable of binding to a proton), such as propylene oxide, to theFe³⁺-containing solution. The Viton®A, A-100 solution is added about 10minutes after the proton scavenger was added to the Fe³⁺-containingsolution. The resulting mixture is very viscous and is stirred to ensurehomogeneous mixing. It is allowed to stand until gel formation takesplace (typically a couple of hours). Once formed, the gel is a dark redmonolith. The gel can be dried under atmospheric conditions or undersupercritical conditions to yield both monoliths or powders. Underatmospheric drying (evaporation under ambient conditions) a xerogel gelis produced, while an aerogel is produced under supercritical drying(solvent exchange under the supercritical conditions). The dryingprocess leads to precipitation of the dissolved Viton®A, A-100 polymerinto the pores of the Fe₂O₃ solid. The materials described in thePreparation and Processing descriptions below have been characterizedherein as described in the section heading Physical Characterization.

[0023] Energetic nanocomposite materials can be formed by adding a fuelmetal powder material, such as, aluminum powder to the Fe₂O₃/Viton®A,A-100 synthetic process. Metals such as Zr, B, Mg, Ti and Al areoxophillic, i.e., they like to form oxides. Oxophillic metals areeffective fuel metal powder materials.

[0024] Fe₂O₃/Viton®A, A-100/Aluminum energetic nanocomposite materialshave been formed by adding ultra fine grained (UFG) aluminum powder withan average particle diameter equal to 40 nm to the homogeneous mixturedescribed above before it is allowed to gel. The stirring action and theUFG nature of the aluminum allow it to form a stable dispersion in thesol-gel solution that upon aging forms a rigid black gel. Referring toFIG. 1, the sol-gel Fe₂O₃ phase 2 grows around and encapsulates thesolid Al particles 4 to form an energetic nanocomposite.

[0025] Viton®A, A-100 is a highly fluorinated polymer, i.e., afluoroelastomer, made commercially by du Pont. It is also known asvinylidine fluoride-hexafluoropropylene copolymer and is commonly usedin energetic materials formulation. Viton®A, A-100 has several usefulproperties that make it an attractive component of energetic materials.Viton®A, A-100 has excellent heat and chemical resistance as well aspossessing lubricant properties in processes such as pressing orextruding. It is also highly fluorinated (60-69%° F. by mass), whichmakes it a strong oxidizer under high temperature and pressureconditions. At high temperatures the fluoroelastomer decomposes togaseous byproducts. Finally, it is one of the few highly fluorinatedpolymers that has significant solubility in common organic solvents. Aspreviously stated, Viton®A, A-100 is soluble in several low molecularweight ketones, and esters.

[0026] A common solvent system can be used as both a solvent forViton®A, A-100 and a medium for the sol-gel Fe₂O₃ synthesis. One solventsystem that works well is a co-solvent that is 70% ethanol and 30%acetone by weight. In this co-solvent system sol-gel Fe₂O₃ can be madewhile keeping the Viton®A, A-100 dissolved. After formation of theporous Fe₂O₃ gel network slow evaporation of the solvent leads toprecipitation of the Viton®A, A-100 polymer throughout theinterconnected cavities of the material to, in effect, entwine theorganic polymer in the inorganic glass. This structure is aninterpenetrating network of both the organic and inorganic components,like that shown in FIG. 1. The degree of mixing and contact between thetwo phases is superb. Any type of mechanical mixing of the two preformedcomponents could not prepare this type of material. Physicalcharacterization of the hybrid Fe₂O₃/Viton®A, A-100 material indicatesthe degree of mixing between the phases.

[0027] Referring to FIG. 2, the Fourier Transform infra-red (FT-IR)spectra of Viton®A, A-100 6 and a sol-gel Fe₂O₃/Viton®A, A-100 xerogelnanocomposite 8 are shown. There are clear strong vibrational bands at883 cm⁻¹, 1205 cm⁻¹, and 1398 cm⁻¹ in the spectra of both materials(note asterisks in FIG. 2). This shows the synthetic process describedabove has resulted in a sol-gel Fe₂O₃ material that contains Viton®A,A-100. Even though the FT-IR evidence indicates the presence of Viton®A,A-100 in the composite material, it provides no information as to thedistribution and degree of mixing of the fluoroelastomer in the glassyinorganic matrix. Measurements of the pore volume and surface area ofthe inorganic/organic nanocomposites provide that information.

[0028] Nitrogen adsorption/desorption experiments were performed onsol-gel Fe₂O₃/Viton®A, A-100 xerogel and aerogel composites that were80% Fe₂O₃/20% Viton®A, A-100 and 100% Fe₂O₃/0% Viton®A, A-100 by weight.The surface area, pore volume, and average pore size for the threematerials are shown in Table 1. TABLE 1 Summary of N₂ adsorption/desorption data for sol-gel Fe₂O₃/Viton ® A, A-100 hybrid materials.B.H.J. Pore B.E.T. Surface Volume Material Area (m²/g) (cm³/g) Fe₂O₃xerogel 453 0.25 Fe₂O₃/Viton ® A, 6.5 <0.005 A-100 xerogel Fe₂O₃ aerogel506 3.55 Fe₂O₃/Viton ® A, 219 1.66 A-100 aerogel

[0029] The nitrogen adsorption data in Table 1 indicates that theViton®A, A-100-containing samples have significantly smaller surfaceareas and pore volumes than control samples with no polymer present.This is most obvious in the xerogel sample and occurs to a smallerextent in the more open network aerogel material, wherein more opennetwork refers to larger pore diameters and pore volumes. Thisobservation is consistent with the fact that the Viton®A, A-100 in thedried samples has effectively filled in the pores of the Fe₂O₃ sol-gelnanostructure (as depicted in FIG. 1).

[0030] Further interpretation of this data suggests that the Viton®A,A-100 is well distributed throughout the nanostructure. If instead, theViton®A, A-100 were present in large (μm-sized) localized domains therewould logically be significant areas consisting of the highly poroussol-gel Fe₂O₃, and one would expect both the surface area and porevolumes to be much higher, especially for the xerogel sample. Theextremely uniform and fine entrainment of Viton®A, A-100 into the porousFe₂O₃ network results in a true nanocomposite. That is, the size of thecomponents and the dimensions of contact between those phases are in thetens of nanometers range (i.e., on the order of the size of the porediameters (15-40 nm)).

[0031] Energy filtered transmission electron microscopy (EFTEM) at LLNLhas been utilized to more fully elucidate the close contact betweenViton®A, A-100 and Fe₂O₃ in this material. EFTEM can be used toconstruct an elemental specific map of a given image. The EFTEMtechnique is performed using conventional TEM microscopy in conjunctionwith very precise magnetic filters (see Mayer, J. European Microscopyand Analysis 1993, 21-23). Use of the magnetic image filtering systemallows the construction of an image from inelastically scattered beamelectrons of a given energy. The energy of the inelastically scatteredelectrons is related to the identity of the elements that it interactswith. By only allowing scattered electrons, of/a given energy, throughthe filter, elemental specific maps of an image can be identified. FIG.3a shows an EFTEM image of a Fe₂O₃/Viton®A, A-100 xerogel, FIG. 3b showsthe EFTEM map for fluorine and FIG. 3c shows the EFTEM map for iron.These images show that fluorine, from the Viton®A, A-100, and iron, fromthe Fe₂O₃ xerogels, are uniformly present throughout the sample. TheEFTEM results indicate that F-containing Viton®A, A-100 to be presentthroughout the sample indicating superb mixing of both the inorganic andorganic phases (as depicted in FIG.

[0032] The sol-gel method allows production of materials with specialshapes such as monoliths, fibers, films, and powders of uniform and verysmall particle sizes. Very fine powders of the hybrid sol-gel Fe₂O₃/UFGAl/Viton®A, A-100 xerogel composites have been produced. Free-standingdry energetic composite pellets have been produced by ambienttemperature or supercritical drying of wet gels without any pressing.Referring to FIG. 4, a Fe₂O₃/UFG Al aerogel composite next to an USpenny is shown. The synthesis and shape casting of low-density energeticmaterials compositions to make monolithic materials in a variety ofshapes and sizes is possible.

[0033] Pressing of nanocomposite powders into dense monoliths produces amaterial with a high energy density. An energetic nanocomposite powdercomprising (all values are weight percentages) 40% sol-gel Fe₂O₃, 38%UFG Al, 11% Viton®A, A-100, and 11% organic oligomers was prepared asdescribed herein in the section labeled Experimental. The organiccomponent of the materials is the byproduct of the sol-gel synthesismethod. A portion of this powder was pressed using a remote apparatus,at a temperature of 80° C., to a pressure of 30,000 psi, with a dwelltime of 3 minutes. FIG. 5 is a photo of a pressed part of sol-gelFe₂O₃/UFG Al/Viton®A, A-100 nanocomposite with a density of 1.93 g/ccnext to a US dime. The density value is between 74-77% of theoreticalmaximum density (TMD) for the material which is 2.5-2.6 g/cc.

[0034] The sol-gel process is very amenable to dip-, spin-, andspray-coating technologies to coat surfaces. Various substrates havebeen dip-coated to make sol-gel Fe₂O₃/Al/Viton®A, A-100 coatings. Theenergetic coating dries to give a nice adherent film. Preliminaryexperiments indicate that films of the hybrid material areself-propagating when ignited by thermal stimulus. Some of the thermalproperties of the sol-gel Fe₂O₃/Al/Viton®A, A-100 nanocomposite havebeen investigated. FIG. 6 contains the differential thermal analysis(DTA) trace of this material in ambient air. The sol-gel nanocompositeDTA has thermal events at ˜260, ˜290, and ˜590° C. The two lowertemperature events have been determined to relate to a phase transitionand crystallization of the amorphous Fe₂O₃ phase. The exotherm at 590°C. corresponds to the thermite reaction (confirmed by powder x-raydiffraction of reaction products). This exotherm is very narrow andsharp, possibly indicating a very rapid reaction. The thermite reactiontakes place at a temperature markedly below the melt phase of bulkaluminum (t_(m)=660° C.). It is commonly thought that in conventionalthermites, the thermite reactions are initiated by the melting ordecomposition of one of the constituent phases (See Wang, L. L.; Munir,Z. A.; Maximov, Y. M. J. Mater. Sci. 1993, 28, 3693-3708 and Mei, J.;Halldearn, R. D.; Xiao, P. Scripta Materialia, 1999, 41(5), 541-548).

[0035] Phenomenological burn observations indicate that the materialburns very rapidly and violently, essentially to completion, with thegeneration Of significant amounts of gas. This reaction is veryexothermic and results in the production of very high temperatures,intense light, and pressure from the generation of the gaseousbyproducts of Viton®A, A-100 decomposition.

[0036] Preparation of sol-gel Fe₂O₃/Al/Viton A hybrid organic/inorganicenergetic nanocomposite: Ferric chloride hexahydrate, FeCl₃.6H₂O (98%),and acetone were obtained from Aldrich Chemical Co. and used asreceived. Absolute (200 proof) ethanol from Aaper was used as received.Viton fluoroelastomer was acquired from E. I. Du Pont de NemoursChemical Co. The ultra fine grain aluminum (UFG Al) used in this studywas provided by the Indian Head Division of the Naval Surface WarfareCenter and was prepared via dynamic vapor phase condensation.Transmission electron microscopy analysis indicated that the UFG had alarge distribution of particle sizes from −10 to −100 nm in diameter.The aluminum content of this material was −70% by weight as determinedby thermal gravimetric analysis.

[0037] In a typical experiment, 1.34 g of FeCl₃.6H₂O (5.0 mmol) wasdissolved in 16 g of a mixed solvent (70% ethanol/30% acetone by weight)to give a clear red-orange solution that remained unchanged uponstorage, under room conditions, for several months. If instead, a 4.8 gportion of propylene oxide was added to the solution it turned darkred-brown color (a variety of different 1,2- and 1,3-epoxides aresuitable for this step of the synthesis). The color change isaccompanied by significant heat generation, which in some cases led torapid boil over of the synthesis solution. To prevent a flash boil the4.8 g of propylene oxide was added in four separate 1.2 g amounts overthe period of about one hour.

[0038] A Viton®RA-containing solution was prepared by dissolving 5 g ofViton®A, A-100 A fluoroelastomer in 85 g of acetone (although acetone isused in this description, Viton®A, A-100 is soluble in a variety of lowmolecular weight esters and ketones, which are also suitable solventsfor this synthesis). After the Viton®A, A-100 had completely dissolved50 g of ethanol was added to the solution. Four grams of this solutionwas added to the propylene oxide containing Fe (III) solution from theprevious paragraph. Then 0.48 g of UFG Al was added to this solutionwhile stirring with a magnetic stir bar. The resulting mixture wasstirred until the gelation occurred. Typical gel times were between15-240 minutes.

[0039] Some nanocomposites were also made without aluminum and some wereprepared using conventional μm-sized Al. Other oxophillic fuel metalpowders (e.g., boron, magnesium, zirconium etc.) could be usedeffectively in this process. In addition, this method is versatileenough that it could be extended to other sol-gel oxide systems (e.g.,MoO₃, NiO, CoO, WO₃, WO₂, MoO₂, MnO₂, CuO, V₂O₅, Ta₂O₅). Finally, thisis a general method for the incorporation of polymers into inorganicmatrices with the only requirement being the solubility of the polymerin a chosen solvent. Thus, the general application of this method to amultitude of other polymers or organic molecules is clearly possible.

[0040] Processing Fe₂O₃/Al/Viton A and Fe₂O₃/Viton A Nanocomposites.

[0041] Aerogel samples were processed in a Polaron™ supercritical pointdrier. The solvent liquid in the wet gel pores was exchanged for CO₂(l)for 3-4 days, after which the temperature of the vessel was ramped up to˜45° C., while maintaining a pressure of 100 bars. The vessel was thendepressurized at a rate of about 7 bars per hour. For aerogelprocessing, polyethylene vials were used to hold the gels during theextraction process. This was done because much less monolith crackingwas observed than when Fe₂O₃ gels were processed in glass vials. Dryingin a fume hood at room temperature for 14-30 days resulted in xerogelsamples. Under these conditions high vapor pressure solvents, likeethanol, were evaporated and the wet gels were converted to xerogels.Drying at elevated temperatures under flowing N₂ atmosphere alsoproduced xerogels. Inert atmospheric drying of xerogels was done underambient and elevated (˜100° C.) conditions.

[0042] The wet pyrotechnic nanocomposites cannot be ignited until thedrying process is complete. However, once dry, the materials will burnrapidly and vigorously if exposed to extreme thermal conditions. Inaddition, the autoignition of energetic nanocomposites has been observedupon rapid exposure of hot ˜100° C. material to ambient atmosphere.

[0043] Physical characterization of Fe₂O₃/Al/Viton®A, A-100 andFe₂O₃/Viton®A, A-100 nanocomposites. Fourier transform-infrared (FT-IR)spectra were collected on pressed pellets containing KBr (IR-grade) anda small amount of solid sample. The spectra were collected with aPolaris™ FTIR spectrometer. Surface area determination, pore volume andsize analysis were performed by BET (Brunauer-Emmett-Teller) and BJH(Barrett-Joyner-Halenda) methods using an ASAP 2000 Surface areaAnalyzer (Micromeritics Instrument Corporation). Samples ofapproximately 0.1-0.2 g were heated to 200° C. under vacuum (10⁻⁵ Torr)for at least 24 hours to remove all adsorbed species. Nitrogenadsorption data was taken at five relative pressures from 0.05 to 0.20at 77K, to calculate the surface area by BET theory. Bulk densities ofboth xerogels and aerogels were determined by measuring the dimensionsand mass of each monolithic sample.

[0044] High resolution transmission electron microscopy (HRTEM) of dryFe₂O₃ gels was performed on a Philips CM300FEG operating at 300 Kevusing zero loss energy filtering with a Gatan energy Imaging Filter(GIF) to remove inelastic scattering. The images where taken under BF(bright field) conditions and slightly defocused to increase contrast.The images were also recorded on a 2K×2K CCD camera attached to the GIF.Differential thermal analysis (DTA) was performed on energeticnanocomposites that were contained in an open platinum pan. Samples wereheated under both room and inert (nitrogen) atmospheres from roomtemperature to 1250° C. at a heating rate of 20° C./min. Powder X-raydiffraction (PXRD) experiments were performed on samples powders mountedon quartz slides and loaded into a CPS120 Curved Position SensitiveDetector unit that utilizes CuK_(α) radiation.

[0045] While various materials, parameters, operational sequences, etc.have been described to exemplify and teach the principles of thisinvention, such are not intended to be limited. Modifications andchanges may become apparent to those skilled in the art; and it isintended that the invention be limited only by the scope of the appendedclaims.

The invention claimed is:
 1. A nanocomposite produced by the processcomprising: dissolving a metal ion salt in a solvent system to form ametal ion salt solution, wherein said solvent system is common to saidmetal ion salt and a polymer; adding an epoxide to said metal ion saltsolution to form an epoxide-containing metal ion salt solution;dissolving said polymer in said solvent system to form a polymersolution; adding a portion of the polymer solution to thepolymer-containing metal ion salt solution to form a polymer-containing,epoxide-containing metal ion salt solution; and stirring said apolymer-containing, epoxide-containing metal ion salt solution untilsaid solution gels.
 2. The nanocomposite produced by the process recitedin claim 1, further comprising: adding a fuel metal powder to saidpolymer-containing, epoxide-containing metal ion salt solution whilestirring, wherein said addition of the fuel metal powder occurs beforesaid polymer-containing, epoxide-containing metal ion salt solutiongels.
 3. The nanocomposite recited in claim 1 wherein said metal oxideis Fe₂O₃.
 4. The nanocomposite produced by the process recited in claim1, wherein said polymer is a fluoroelastomer.
 5. The nanocompositeproduced by the process recited in claim 2, wherein said fluoroelastomeris Viton®A, A-100.
 6. The nanocomposite produced by the process recitedin claim 1 wherein Viton®A, A-100 is soluble in said solvent system. 7.The nanocomposite produced by the process recited in claim 1, whereinsaid solvent system is a mixture of ethanol and acetone.
 8. Thenanocomposite produced by the process recited in claim 2, wherein saidfuel metal powder is Al, Mg, B, Ti, Zr or mixtures thereof.
 9. Thenanocomposite produced by the process recited in claim 2, wherein saidfuel metal powder is ultra fine grain aluminum.
 10. A nanocompositecomprising: an inorganic sol-gel polymer phase comprising at least onemetal-oxide and at least one epoxide; and an interpenetrating organicpolymer phase entwined in said inorganic sol-gel phase.
 11. Thenanocomposite recited in claim 10, wherein said inorganic sol-gelpolymer phase further comprises: A fuel metal powder.
 12. Thenanocomposite recited in claim 10, wherein said metal oxide is Fe₂O₃.13. The nanocomposite recited in claim 10, wherein said polymer is afluoroelastomer.
 14. The nanocomposite recited in claim 13, wherein saidfluoroelastomer is Viton®A, A-100.
 15. The nanocomposite recited inclaim 11, wherein said fuel metal powder is Al, Mg, B, Ti, Zr ormixtures thereof.
 16. The nanocomposite recited in claim 11, whereinsaid fuel metal powder is ultra fine grain aluminum.